lignosulfonates, microsilica, stpp exports from Russia

Advanced research and development programs have spearheaded the widespread use of silica fume in numerous applications.

Concrete
High Performance Concrete (HPC) containing silica fume – has been identified as one of the more important advanced materials necessary in the effort to rebuild the nations infrastructure. In addition to increased strength and enhanced durability, HPC produced with silica fume delivers increased toughness; increased resistance to abrasion, corrosion and chemicals; and placement and life-cycle cost efficiencies.
Highway bridges, parking decks, marine structures and bridge deck overlays are subject to constant deterioration caused by rebar corrosion current, abrasion and chemical attack. Silica fume will protect concrete against deicing salts, seawater, road traffic and freeze/thaw cycles. Rebar corrosion activity and concrete deterioration are virtually eliminated, which minimizes maintenance expense.
Key benefits include:
Very low permeability to chloride and water intrusion.
Extremely high electrical resistivity (20 to 100 times greater than ordinary concrete).
Increased abrasion resistance on decks, floors, overlays and marine structures.
Superior resistance to chemical attack from chlorides, acids, nitrates and sulfates.
High-strength concrete enhanced with silica fume – provides architects and engineers with greater design flexibility. Traditionally used in high-rise buildings for the benefit of smaller columns (increasing the usable space) high-strength concrete containing silica fume is often used in precast and prestressed girders allowing longer spans in structural bridge designs.
Key advantages include:
Compressive strengths up to 20,000 psi (140 Mpa)
High modulus of elasticity exceeding 6 million psi (40,000 Mpa)
High flexural strengths (2,000 psi @ 28 days) for airport pavements
High early strengths for fast-track construction projects and precast applications

Trump Palace, NY
A 56-story luxury residential high-rise tower utilized 1,200 cubic yards silica-fume concrete in the structural columns. Specified compressive strength 12,500 at 28 days was achieved with the addition of 11% of silica fume.

Shotcrete
Silica-fume Shotcrete – delivers greater economy, greater timesavings and more efficient use of sprayed concrete. Silica fume produces superior shotcrete for use in rock stabilization; mine tunnel linings, and rehabilitation of deteriorating bridge and marine columns and piles. Greater bonding strength assures outstanding performance of both wet and dry process shotcreting with less rebound loss and thicker applications with each pass of the shotcrete nozzle.
Superior performance characteristics are:

• Reduction of rebound loss up to 50%
• Improved production time, with one-pass application thicknesses up to 12 inches
• Higher bonding strength
• High electrical resistivity and low permeability
• High compressive and flexural strengths

KANSAS CITY INTERNATIONAL AIRPORT :650,000 square foot parking garage placed with silica-fume concrete. Average compressive strength was 3,965 psi at 2 days for post tensioning. Rapid chloride permeability (RCP) value of 250 coulombs was achieved with the addition of 10% of silica fume.

Oil Well Grouting
Whether used for primary (placement of grout as a hydraulic seal in the wellbore) or secondary applications (remedial operations including leak repairs, splits, closing of depleted zones), the addition of silica fume enables a well to achieve full production potential. Besides producing a blocking effect in the oil well grout that prevents gas migration, it provides these advantages:

• Improved flow, for easier, more effective application
• Dramatically decrease permeability, for better control of gas leakage
• Increased durability and compressive strength
• Lightweight

Repair Products (Mortars & Grouts)
Silica fume is used in a variety of cementitious repair products. Mortars or grouts modified with silica fume can be tailored to perform in many different applications—overhead and vertical mortars benefit from silica fume’s ability to increase surface adhesion. Silica fume dramatically improves cohesiveness making it ideal for use in underwater grouts, decreases permeability in grouts used for post-tensioning applications and increases the resistance to aggressive chemicals.

• Non-bleeding and non-segregating
• Low permeability
• Lightweight
• Increased resistance to attack from chlorides, acids, nitrates and sulfate

Refactory and Ceramics
The use of silica fume in refractory castables provides better particle packing. It allows for less water to be used while maintaining the same flow characteristics. It also promotes low temperature sintering and the formation of mullite in the matrix of the castable. This produces a castable that has a low permeability to avoid gas, slag and metal penetration. Castables incorporating silica fume are stronger than non-silica fume containing castables especially at high temperatures with higher density they attain lower porosity and are more volume stable.